TableĀ 2.

Rock mass weathering grades

TermDescriptionGrade
FreshNo visible sign of rock material weathering; perhaps slight discoloration on major discontinuity surfaces.0
Slightly weatheredDiscoloration indicates weathering of rock material and discontinuity surfaces.1
Moderately weatheredLess than half of the rock material is decomposed or disintegrated. Fresh or discoloured rock is present either as a continuous framework or as core stones.2
Highly weatheredMore than half of the rock material is decomposed or disintegrated. Fresh or discoloured rock is present either as a discontinuous framework or as core stones.3
Completely weatheredAll rock material is decomposed and/or disintegrated to soil. The original mass structure is still largely intact.4
Residual soilAll rock material is converted to soil. The mass structure and material fabric are destroyed. There is a large change in volume, but the soil has not been significantly transported.5

After ISO 14689-1:2003 2003.